The resistances of the four arms P, Q,R and S in a Wheatstone's bridge are 10Ω ,30Ω ,30Ω and 90Ω, respectively. The emf and internal resistance of the cell are 7 V and 5 Ω respectively. If the galvanometer resistance is 50Ω, the current drawn from the cell will be

1. 1.0A
2. 0.2A
3. 0.1A
4. 2.0A

 

In the circuit shown the cells A and B have negligible resistances. For $V_A=12V, R_1=500\Omega and R=100\Omega$ the galvanometer (g) shown no deflection. The value of $V_B$ is 

1. 4V                                         
2. 2V
3. 12V                                       
4. 6V

If voltage across a bulb rated 220 V-100 W drops by 2.5% of its rated value, the percentage of the rated value by which the power would decrease is

1. 20%                                             

2. 2.5%

3. 5%                                               

4. 10%

The power dissipated in the circuit shown in

the figure is 30 Watt. The value of R is :

1. $20\mathrm{\Omega }$

2. $15\mathrm{\Omega }$

3. $10\mathrm{\Omega }$

4. $30\mathrm{\Omega }$

If power dissipated in the 9$\mathrm{\Omega }$ resistor in the circuit shown is 36 W, the potential difference across the 2$\mathrm{\Omega }$ resistor is

1. 8 V
2. 10 V
3. 2 V
4. 4 V

In the circuit in the figure, if the potential at point A is taken to be zero, the potential at point B is :

1. -1V                                          2. +2V

3. -2V                                          4. +1V

                         
1. \(0.6\pi~\Omega\)
2. \(3~\Omega\)
3. \(6\pi~\Omega\)
4. \(6~\Omega\)

See the electrical circuit shown in this figure. Which of the following equation is a correct equation for it?

1. ${\epsilon }_1-\left(i_1+i_2\right)R-i_1{r}_1=0$

2. ${\epsilon }_2-i_2{r}_2-{\epsilon }_1-i_1{r}_1=0$

3. $-{\epsilon }_2-\left(i_1+i_2\right)R+i_2{r}_2=0$

4. ${\epsilon }_1-\left(i_1+i_2\right)R+i_1{r}_1=0$

A wire of a certain material is stretched slowly by ten per cent. Its new resistance and specific resistance become respectively 1. .

A cell can be balanced against 110cm and 100 cm of potentiometer wire, respectively with and without being short-circuited through a resistance of $10 \Omega$. Its internal resistance is 

1. 1.0 $\Omega$

2. 0.5 $\Omega$

3. 2.0 $\Omega$

4. zero